Disposal of used electronic equipment, parts, and components, including obsolete or damaged computers, computer monitors, television receivers, cellular telephones, and similar products, is increasing at a rapid rate. It is recognized that there are significant hazards to living things and to the environment generally when electronic equipment is dumped in landfills. Equally, it is understood that improper disassembly poses appreciable risks to the health and safety of people performing disassembly manually.
There are known systems and methods for recovering materials from printed circuit boards, including disassembling circuit boards, for example as described in U.S. Pat. No. 5,758,817 issued Jun. 2, 1998 to Chapman (hereinafter “the '817 patent”), and including crushing or otherwise breaking circuit boards into fine particles, for example as described in U.S. Pat. No. 5,667,156 issued Sep. 16, 1997 to Chapman (hereinafter “the '156 patent”).
As described in the '817 patent, an automated system is disclosed that employs radiant heating unit(s) positioned beneath printed wiring assemblies (“PWA's”) that are transported through the disassembly apparatus. In addition, some preferred embodiments described in the '817 patent use a photo sensor and two PWA vibrating plunging devices. The photo sensor detects the approaching PWA. These sensors may be placed in a way that provides an option to detect either the leading or the trailing edge of the boards as they are transported. When a PWA passes under the photo sensor, a de-population circuit control module activates a vibrating plunger device. The plunger of a vibrating plunger device strikes a selected place on a Printed Wiring Board (PWB) of a PWA, such as the back, uppermost portion of a PWB once the solder holding electrical components reaches its melt-flow temperature. Vibrating plunging devices then vibrate a PWA at the appropriate time in the appropriate position to create a vibration, which causes electrical components to drop or fall off of the PWB.
The '156 patent describes that use of a plurality of crushing machines and conveyors to reduce PWAs and PWBs to particulate material. The PWAs or PWBs are rendered into three fractions, described as (A) a granular form of the metallic constituent that allows reproducible and reliable chemical analysis of its elemental composition and permits efficient reclamation of the precious elements through subsequent refining processes; (B) a finely ground form of non-metallic PWB base material, generally comprising fiberglass and epoxy or polyimide resin, a “fines” fraction; and (C) an extremely finely ground form of non-metallic dust generally comprising the fiberglass and binding resins from the PWB base. The '156 patent teaches that these fractions can be reclaimed or recycled.
There is a need for systems and methods that allow the recovery in an environmentally friendly way of components, precious materials, and also energy from discarded electronic components such as printed circuit boards.